altos/lisp: Make lambda, cond and while all have implicit progns

This lets all of these execute more than one sexpr, returning the
value of the last.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/lisp/ao_lisp_eval.c b/src/lisp/ao_lisp_eval.c
index 6f56a1205aee9a561e070dc68327175880af17d7..5fa9e0ad47a25ebbde49557b315ae41fd4e6ff1b 100644 (file)
--- a/src/lisp/ao_lisp_eval.c
+++ b/src/lisp/ao_lisp_eval.c
@@ -310,7 +310,6 @@ ao_lisp_eval_formal(void)
                         * value and re-evaluate it
                         */
                        prev = ao_lisp_poly_stack(ao_lisp_stack->prev);
-                       ao_lisp_stack->state = eval_sexpr;
                        ao_lisp_stack->sexprs = prev->sexprs;
 
                        DBGI(".. start macro\n");
@@ -401,10 +400,11 @@ ao_lisp_eval_exec(void)
                DBGI(".. frame "); DBG_POLY(ao_lisp_frame_poly(ao_lisp_frame_current)); DBG("\n");
                break;
        case AO_LISP_LAMBDA:
-               ao_lisp_stack->state = eval_sexpr;
                DBGI(".. frame "); DBG_POLY(ao_lisp_frame_poly(ao_lisp_frame_current)); DBG("\n");
-               ao_lisp_v = ao_lisp_lambda_eval();
-               DBGI(".. sexpr "); DBG_POLY(ao_lisp_v); DBG("\n");
+               ao_lisp_stack->state = eval_progn;
+               v = ao_lisp_lambda_eval();
+               ao_lisp_stack->sexprs = v;
+               DBGI(".. sexprs "); DBG_POLY(ao_lisp_stack->sexprs); DBG("\n");
                DBGI(".. frame "); DBG_POLY(ao_lisp_frame_poly(ao_lisp_frame_current)); DBG("\n");
                break;
        }
@@ -442,7 +442,6 @@ ao_lisp_eval_cond(void)
                ao_lisp_stack->state = eval_cond_test;
                if (!ao_lisp_stack_push())
                        return 0;
-               ao_lisp_stack->state = eval_sexpr;
        }
        return 1;
 }
@@ -464,11 +463,11 @@ ao_lisp_eval_cond_test(void)
        DBGI(".. saved frame "); DBG_POLY(ao_lisp_stack->frame); DBG("\n");
        if (ao_lisp_v) {
                struct ao_lisp_cons *car = ao_lisp_poly_cons(ao_lisp_poly_cons(ao_lisp_stack->sexprs)->car);
-               struct ao_lisp_cons *c = ao_lisp_poly_cons(car->cdr);
+               ao_poly c = car->cdr;
 
                if (c) {
-                       ao_lisp_stack->state = eval_sexpr;
-                       ao_lisp_v = c->car;
+                       ao_lisp_stack->state = eval_progn;
+                       ao_lisp_stack->sexprs = c;
                } else
                        ao_lisp_stack->state = eval_val;
        } else {
@@ -502,6 +501,10 @@ ao_lisp_eval_progn(void)
        } else {
                ao_lisp_v = ao_lisp_poly_cons(ao_lisp_stack->sexprs)->car;
                ao_lisp_stack->sexprs = ao_lisp_poly_cons(ao_lisp_stack->sexprs)->cdr;
+
+               /* If there are more sexprs to do, then come back here, otherwise
+                * return the value of the last one by just landing in eval_sexpr
+                */
                if (ao_lisp_stack->sexprs) {
                        ao_lisp_stack->state = eval_progn;
                        if (!ao_lisp_stack_push())
@@ -530,7 +533,6 @@ ao_lisp_eval_while(void)
                ao_lisp_stack->state = eval_while_test;
                if (!ao_lisp_stack_push())
                        return 0;
-               ao_lisp_stack->state = eval_sexpr;
        }
        return 1;
 }
@@ -547,11 +549,11 @@ ao_lisp_eval_while_test(void)
 
        if (ao_lisp_v) {
                ao_lisp_v = ao_lisp_poly_cons(ao_lisp_stack->sexprs)->cdr;
-               if (ao_lisp_v)
-                       ao_lisp_v = ao_lisp_poly_cons(ao_lisp_v)->car;
                ao_lisp_stack->state = eval_while;
                if (!ao_lisp_stack_push())
                        return 0;
+               ao_lisp_stack->state = eval_progn;
+               ao_lisp_stack->sexprs = ao_lisp_v;
        }
        else
                ao_lisp_stack->state = eval_val;
@@ -567,6 +569,8 @@ ao_lisp_eval_macro(void)
 {
        DBGI("macro: "); DBG_POLY(ao_lisp_v); DBG(" sexprs "); DBG_POLY(ao_lisp_stack->sexprs); DBG("\n");
 
+       if (ao_lisp_v == AO_LISP_NIL)
+               ao_lisp_abort();
        if (ao_lisp_poly_type(ao_lisp_v) == AO_LISP_CONS) {
                *ao_lisp_poly_cons(ao_lisp_stack->sexprs) = *ao_lisp_poly_cons(ao_lisp_v);
                ao_lisp_v = ao_lisp_stack->sexprs;

diff --git a/src/lisp/ao_lisp_lambda.c b/src/lisp/ao_lisp_lambda.c
index 186236f6eb7e8f3e5373050dbac8a76b48684b61..e2053a6f3d4302e15e17c75c3dfe21cc8be90258 100644 (file)
--- a/src/lisp/ao_lisp_lambda.c
+++ b/src/lisp/ao_lisp_lambda.c
@@ -78,8 +78,9 @@ ao_lisp_lambda_alloc(struct ao_lisp_cons *code, int args)
        if (!lambda)
                return AO_LISP_NIL;
 
-       if (!ao_lisp_check_argc(_ao_lisp_atom_lambda, code, 2, 2))
-               return AO_LISP_NIL;
+       if (!code->cdr)
+               return ao_lisp_error(AO_LISP_INVALID, "missing parameters to lambda");
+
        if (!ao_lisp_check_argt(_ao_lisp_atom_lambda, code, 0, AO_LISP_CONS, 1))
                return AO_LISP_NIL;
        f = 0;
@@ -135,7 +136,7 @@ ao_lisp_lambda_eval(void)
        int                     args_wanted;
        int                     args_provided;
        int                     f;
-       struct ao_lisp_cons     *vals
+       struct ao_lisp_cons     *vals;
 
        DBGI("lambda "); DBG_POLY(ao_lisp_lambda_poly(lambda)); DBG("\n");
 
@@ -161,6 +162,10 @@ ao_lisp_lambda_eval(void)
        args = ao_lisp_poly_cons(ao_lisp_arg(code, 0));
        vals = ao_lisp_poly_cons(cons->cdr);
 
+       next_frame->prev = lambda->frame;
+       ao_lisp_frame_current = next_frame;
+       ao_lisp_stack->frame = ao_lisp_frame_poly(ao_lisp_frame_current);
+
        switch (lambda->args) {
        case AO_LISP_FUNC_LAMBDA:
                for (f = 0; f < args_wanted; f++) {
@@ -171,6 +176,7 @@ ao_lisp_lambda_eval(void)
                        vals = ao_lisp_poly_cons(vals->cdr);
                }
                ao_lisp_cons_free(cons);
+               cons = NULL;
                break;
        case AO_LISP_FUNC_LEXPR:
        case AO_LISP_FUNC_NLAMBDA:
@@ -182,15 +188,15 @@ ao_lisp_lambda_eval(void)
                        args = ao_lisp_poly_cons(args->cdr);
                        vals = ao_lisp_poly_cons(vals->cdr);
                }
-               DBGI("bind "); DBG_POLY(args->car); DBG(" = "); DBG_POLY(); DBG("\n");
+               DBGI("bind "); DBG_POLY(args->car); DBG(" = "); DBG_POLY(ao_lisp_cons_poly(vals)); DBG("\n");
                next_frame->vals[f].atom = args->car;
                next_frame->vals[f].val = ao_lisp_cons_poly(vals);
                break;
+       default:
+               break;
        }
-       next_frame->prev = lambda->frame;
        DBGI("eval frame: "); DBG_POLY(ao_lisp_frame_poly(next_frame)); DBG("\n");
-       ao_lisp_frame_current = next_frame;
-       ao_lisp_stack->frame = ao_lisp_frame_poly(ao_lisp_frame_current);
        DBG_STACK();
-       return ao_lisp_arg(code, 1);
+       DBGI("eval code: "); DBG_POLY(code->cdr); DBG("\n");
+       return code->cdr;
 }